The Work and Pensions secretary said the real welfare reform would come when Government and families accepted the bill had to come down.

An estimated five million people of working age on out-of-work benefits - 1.4 million of whom have been on benefits for nearly a decade.

Mr Duncan Smith’s department is currently working through a radical plan to cut billions from the benefits budget.

Out-of-work benefit bills are being capped at £26,000 a year, while a single universal credit for millions of people will come into force next year. But he said that simply “recalibrating” the system was not enough.

However, in a speech to the Policy Exchange think tank on Wednesday evening, Mr Duncan Smith said that what the UK needs “in the coming years is not political and technocratic welfare reform, but internal and cultural change”.

He added: “By this I mean cultural change both within society, and within Government itself. We are faced with a fundamental challenge. Millions of people stuck on out of work benefits. Millions not saving nearly enough for their retirement.

“And Government addicted to spending levels as a measurement of success, rather than life change as a measurement of success.”

Mr Duncan Smith said that the “answer” to the problems in the benefit system was to “change the way you reform”.

He added: “Not just cheese-slicing, but recalibrating whole systems so that you change behaviours, and change the culture that allowed spending to get out of control in the first place.”